You already have enabled debug mode in the first call to SPCascadeDropdowns by setting debug: true. If there's a problem, then a message box will pop up.

The alert would look something like this: alert("Hi, pinky2009!"); and you would put it immediately below the
$(document).ready(function() { line. If the alert pops up, then you know that the jQuery library is referenced correctly.

The two columns relationshipList and relationshipListParentColumn need to be the StaticName of the column. These are the underlying column names which never change, no matter how many times you might rename them. You can see this name
by going into the List Settings and clicking on one of the columns. The StaticName will be on the URL, but may be encoded.

The two columns parentColumn and childColumn need to be the DisplayNames, which are the names that you've actually see on the form.

Here are a few examples:

CountryName: The Display name is CountryName, the StaticName is CountryName

Country Name: The Display name is Country Name, the StaticName is Country_x0020_Name